This invention relates to a positively chargeable toner used in electrophotography and electrostatic recording, more particularly to a positively chargeable toner suitable for carrying out color development in the above-mentioned fields.
As developing methods in these fields, there has been known a dry developing method wherein there is used a developer prepared by mixing fine toner particles containing a charge control agent with a carrier particles such as glass beads, iron powders, or the like. As the positive charge control agent used for positively chargeable toner in the dry development, there has been known, for example, fatty acid modified nigrosines as disclosed in U.S. Pat. No. 3,647,696. But since these charge control agents are colored in dark brown, they can be used in black toners using carbon black as a colorant but cannot be used for blue, yellow, red and the like color toners. U.S. Pat. No. 4,021,358 discloses polyamine resins as a positive charge control agent. These charge control agents are colorless and can be used for color toners, but they have disadvantages in that their compatibility with resins is poor and their dispersibility is also poor. Further, there is another disadvantage in that when a toner is produced by a melt kneading process, an unpleasant amine odor is released.